27 November 1989 Granite, A New Very High Energy 7-Ray Telescope
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A collaboration of astrophysicists from Iowa State University, University of Michigan, the Smithsonian Astro-physical Observatory, England, and Ireland plan to construct a new 10-meter diameter γ-ray Cerenkov telescope on Mt. Hopkins in Arizona. By operating in coincidence with the original 10-meter reflector, the sensitivity for 7-ray detection will improve by more than an order of magnitude. This increase will permit observation of compact objects with the intrinsic luminosity of the Crab nebula which lie within a range of 7 kiloparsecs. The new telescope, named GRANITE (for Gamma-Ray Astrophysics New Imaging Telescope), will include a 109 element imaging photon detector with a 0.2° pixel size. The entire system consists of a steerable alti-azimuth mount, a faceted mirror assembly, a highly segmented photon detector, and ancilliary data acquisition and control electronics. The reflector mount will be fabricated using techniques developed for satellite communications dishes. The mirrors will be second-surface aluminized borosilicate glass optimized for wavelengths in the range of 300 to 400 nanometers. Signals from the photomultiplier detector array will be characterized and recorded according to their amplitude, time of arrival, and width. Each of these subsystems will be described with an emphasis on the trade-offs between cost and instrument performance. This telescope is considered an engineering prototype for a large array of aerenkov detectors which will further enhance our ability to detect astrophysical sources of very high energy gamma rays.
© (1989) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Carl W. Akerlof, Carl W. Akerlof, Donald I. Meyer, Donald I. Meyer, Richard C. Lamb, Richard C. Lamb, David A. Lewis, David A. Lewis, } "Granite, A New Very High Energy 7-Ray Telescope", Proc. SPIE 1159, EUV, X-Ray, and Gamma-Ray Instrumentation for Astronomy and Atomic Physics, (27 November 1989); doi: 10.1117/12.962585; https://doi.org/10.1117/12.962585

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